Production of polyamides



2,946,171 iRoDUCTIoNoFroLYNnDEs Denis George Harold Ballard, Holyport, near Maideny head, Clement Henry Bamford, Beaconsfield, William` Edward Hanby, Oaken Grove, Maidenhead, and Frederick John Weymouth, Styvechale, Coventry, England,

assignors to lCourtaulds Limited, London, England, a

British company 1 n Y No yrawing. Filed Jan, 22, 19-58, Ser. No.' 710,425VV VClaims priority, application Great Britain FebtZZ, 1955 s Claims. (ci. 26o-17,5)

,This invention'relates to the production of polyamides.

application isa continuation-impart application 'ofV our application. No. I563,203 'tiled Feb. -.3,-'-19`56,v now abandoned. www' v l This invention Yis particularly concerned with .the production ofisynthetic 'polypeptides by polymerising anhydrocarboxyamino-acids having the general formula .being an alkylfor aralkyl group,rfwhich may be substi- United States Patent ing` an ionization` constant. -at 25 C., in the krange y 2,946,771 Y. yFe'teniied July 26, 1960 FIce beenproposedinBritish patent specication pl`lo."653,"597l" v touse as Ycatalyststhe sodium or potassium salt, ofjan alpha-'aminocarboxylic acid.`

The object of this invention is to promote Arapid polyl merisation of anhydrocarboxyamino-acids.

In accordance with the' present invention the polymerizgationof one ormore Vacuhydrooarboxy-annuo-acidsis eiectedjin solution inthe presence of Aaimono-carboxylit':zl

. acid-salt having the generali'formula.QRJCQO-Q,n Xnfl' in which R.COO." is -theianionE of al mono-carboxylic-acid hug a dissociation.. constant of y'lesls thanYZXl-O-'R is an alkyl, aryl or aralkyl group andXn-tjis fthe cation of an alkali metal, an alkaline earthlnetal-or'- anfllt-yhtertiary `base," n'representing thevalency of the cation.

Preferredfexamples of such'salts arevpotassium 'aceta'teji sodium acetate, sodium phenyl acetate, potassium y"o`1'"' sodium benzoate, and tri-n-butyl-amine acetate. examplesof suitable salts arevsodiu'mgand potassium propionates,'b utyrates and dihydroxy cinuamates{tri-'normal-y tuted with an: inactive substituent group such as an ester group. Examples` of suitable anhydrocarboxyamino acids are as follows, the A group being indicated in brackets; Y

The anhydrocarboxyamino acid of gamma-benzyl-L- glutamate (C6H5-CH2-O-OC-CH2-CH2-), of'DlL-V beta-phenyl-alauine (C6H5--CH24-L or D,L andv DL- alanine (-CH3) of gamma methyl L glutamate (CH3-O-.OC-CH2'-CH2-), of leucine (CHa-CHz-.CH- Ha of isoleucine of noeucine (CHaj-cHz-CHzLCHz-), of epsilon-N carboxy-benzoxy lysine (C6H5-CH2-'-O-'OC-NI-L-` (CH3-C O O-GCH?) .and also alpha-amino-N-butyric-anhydrocarboxy amino It is known that anhydrocarboxyamno-acids can be` polymerised by heating, either alone or inthe presence of certain catalysts, `the polymerisationY being accompanied by the evolution of carbon dioxide. The catalysts generally proposed hitherto are water and combutyl amine propionateand butyrate; lithium acetate`,lpropiouate and butyrate; calcium andlstrontium -acetates,` propionates, butyrates and benzoates; sodium and potassiumAnaphthalates and sodium and potassium ortho, metaand para-toluates. y The metal salts may be added to` the anhydrocarboxylamino-acid as a tine dispersionor insolution for example in N-methyl formamide.

'Ille polymerisation of the anhydrocarboxyami'uo-acidv is effected in solution. Suitable solvents arebenzene, nitrobenzene, chlorbenzene, acetophenone, dioxane, methylene chloride, chloroform, dimethyl formamide and mixtures of these compounds, theY actual choice of solventy depending on the solubility properties' of the originall anhydrocarboxyamino-acid or acids and the resulting polypeptide. The polymerisation can be carried out at varying temperatures; temperatures ranging from 0 to 100` C. ,have been used successfully; Foreconomic reasons it is preferred to carry out the polymerisation at temperatures. t

yThe invention is illustratedby the following examples in which parts are by Weight. Y

ordinary Example 1 The polymer was precipitated by the addition of 2000 par-ts of ether.

'Ihe product obtained was a colourless .fibre-forming polymer; its reduced viscosity in dichloracetic acid was 0.97. In these examples reduced viscosity is deiined as 'f7-YP in which nsp is the speciiic viscosity of a solution having a concentration (c) of 0.5 gram per cc.

Other v 3 Example 2 5 parts of the N-carbonic anhydride of 'y-benzyl-L- glutamate were dissolved in 100 parts of dioxane and a solution of :04 partv of sodium phenyl acetate 1.32 mol percent based on the weight of the anhydride) dissolved in l part of N-methyl formamide was added with stirring. After the solution had been stirred for 2 hours at 25 C. in an evacuated container, the polymer was precipitated by adding ether as in Example 1.

The product obtained was a colourless fibre-forming polymer;` its reduced viscosity in dichloracetic acid was 1.85.

The procedure described in Example 1 Wasrepeated With the only exception that the potassium acetate was replaced by its molar equivalent (0.035 part) of sodium benzo/at'e. A similar type of polymerto that of Example l was obtained, its reduced viscosity being 0.90.

Example 4 p 5 parts of the `N-carbonicanhydride of y-benzyl-b glutamate were dissolved in 100 parts of dioxaney and a solution of 0.015 part of acetic lacid `and 0.046 part yof tri-nfbutyl-amine in 1 part of ydioxanev 'was" added with stirring. The solutionwas stirred for 1'6'vhours at 25v C. in anevacuated vessel. inExample l.

The product obtained was a colourlessi libre-'forming polymer; its' reduced viscosity inv dichloracetic acid was 1.64.

Exampleb' 3l parts of the N-carbonic anhydride of DL--phenyl alanine were dissolved in 130 parts of nitrobenzene and a solution of 0.05 part of potassium acetate (3.3 mol percent based onV the Weight of the anhydride) in 5 parts of N-methyl formamide was added with stirring. The solution was allowed to st'a'nd for 16 hours in a closed vessel at 25 C. and the product was then precipitated by adding 500 parts of ether. l y

The product obtainedh-ad a reduced viscosity in dichloracetic acid of 0.29.

Example 6 50 grams of the .Nl-carbonio anhydride of D-'alanine were'dissolved in a litre of a mixed solvent consisting of equalI volumes of N-N-dirnethyl form-amide and nitrojbenzene. 0.36 gram of sodiumacetate Ywas thenV added with stirri'n'g and the mixture was allowed to standy for 16 hours. Y

Thev polymer was precipitated' with ether, ltered,

washedl with ether and dried. The polymer was thenv washed with water to remove the initiator and redried. The yieldl was 851percent`. The reduced viscosity of the polymer in tliuoracetic'acid was 0.66.

The polymer was precipitated arsv 4 Examples 7-13 The procedure described in Example 6 was repeated using amounts of initiator given in the table below: the table also includes the reduced viscosity of the polymer measured in triuoracetic acid;

Catalyst Example N. Reduced Y Viscosity 0.72 g. of sodium acetate--; 0. 10

1.23 g. of potassium acetate 0.08

0.86 g.. of potassium acetate 0. 10

0.431g. of potassium acetate 0,12

3.44 g. of calcium acetate 0.08

0.69 g. of calcium acetate 0.14

0.34 g. of calcium acetate 0. 11

The yields in these examples varied foni'SO-SSpercent.

What We claim is:

1. A process for the production of polyamide's cornprising dissolving in a solvent chosen fro'rny the rgroup cosisting of benzene, nitroberizene,A chlo'robenlzen'e",l aceto'-v phenone, dioxane, methylene chloride, chloroform; di'-A methyl formamide, and mixtures of these compounds, at

least one anhydrocarboxyamino' acid having thel general formula:

IX en -(11 oV N O where A is a radical chosen from the group consisting of alkyl, aralkyl, and alkyl and' aryl groups substituted by an ester group, and, as polymerisation initiator, a monocarboxylic acid salt having- 2 1103, R is a radical chosen from the groupAc'onsi's'tf'v ing of alkyl, aryl and aralkyl groups, Xn+ is the cation 'of a radical chosen from the group' consistingV of the alkaliv metals, alkaline earth metals and alkylte'ritafry'ba's'es andr 5. Avprocess as claimed in claim 1 in which the monocarboxylic acid salt used is tri-n-butylamiie' acetate;

No refe'rence's'cite'clly the lgen'eral' :fori'lulaj (R.COO)nXn+ in which'RCOO'- isthe anion of a" mofn'or' carboxylicvacid having a dissociation constant'of lesstha- UNITED STATES PATEM; OFFICE CERTIFICATION OF CORRECTION Patent No. 2,946,771 July 26U 1960 Denis` George Harold Ballard et all@` It is hereby certified that error appears in the above numbered patent requiring correction and that the seid Letters Patent should read as corrected below.

Column 4, line 34, for fan ester group" read fm a selected from the class consisting of the (EIwIg-,CILIQOOCm1 and CH3OO- groups f-.

Signed and Sealed thisl 2nd day of May 1961.

group (SEAL) Attest:

ERNEST W0 SWIDER DAVID L LADD Attesting Officer Commissioner of Patents 

1. A PROCESS FOR THE PRODUCTION OF POLYAMIDES COMPRISING DISSOLVING IN A SOLVENT CHOSEN FROM THE GROUP CONSISTING OF BENZENE, NITROBENZENE, CHLOROBENZENE, ACTEOPHENONE, DIOXANE, METHYLENE CHLORIDE, CHLOROFORM, DIMETHYL FORMAMIDE, AND MIXTURES OF THESE COMPOUNDS, AT LEAST ONE ANHYDROCARBOXYAMINO ACID HAVING THE GENERAL FORMULA: 